For my country I guess it was not a defeat but an incident...Battle of Karánsebes. In this battle the Cavalry and the Infantry of the Austrian army starting killing each other for booze.
The story was that some locals sold the Calvary some booze and they did not want to share with the Infantry. Effect was, a huge brawl with 100,000 soldiers involved and 10,000 casualties. More on Battle of Karánsebes - Wikipedia, the free encyclopedia
Thats the real pride of the Austrian Army...

Basically every American attempt to conquer Canada ended laughably. The Fall of the Philippines also comes to mind since we really should have been more prepared, and as we later saw, the Japanese army was significantly worse than ours.

Battle of Washington D.C., the armies of the British Empire march into the nations capitol and burn it to the ground. With no American armies anywhere to be seen.

I don't really see that as being all that humiliating personally, especially when compared to some other defeats in American military history.

Washington D.C. was little more than a provincial backwater at the time and didn't have the global importance that it has today. European Wars typically ended in disaster for the side whose capital city fell, but since the U.S. at the time was overwhelmingly an agrarian nation with a weak federal government and state governments that enjoyd a high degree of autonomy, the fall of its national capital had little consequence. The American capital fell during both the American Revolution (Philadelphia) and the War of 1812, and in both wars it had no impact on the outcome.

I don't really see that as being all that humiliating personally, especially when compared to some other defeats in American military history.

Washington D.C. was little more than a provincial backwater at the time and didn't have the global importance that it has today. European Wars typically ended in disaster for the side whose capital city fell, but since the U.S. at the time was overwhelmingly an agrarian nation with a weak federal government and state governments that enjoyd a high degree of autonomy, the fall of its national capital had little consequence. The American capital fell during both the American Revolution (Philadelphia) and the War of 1812, and in both wars it had no impact on the outcome.

While i admit all your points are quite valid, surly you would admit that the burning of one's capitol is very demoralizing and a blow to your national prestige. Plus how impotent must the Republic felt knowing that they could never return the favor. Since they had no chance of ever coming close to London.

Battle of Washington D.C., the armies of the British Empire march into the nations capitol and burn it to the ground. With no American armies anywhere to be seen.

I would add:
Kasserine Pass--> A bunch of Italo-German units, though led by Rommel, drove Americans.
In fact, Americans were unexperienced soldiers fighting against veterans, therefore it is not really humiliating.

battle of Sarıkamış is one for the ottoman empire. the lunatic and great idiot called enver paşa sent thousands of soldiers without proper clothing and equipment against the imperial russian army. many of the ottoman soldiers were killed of cold and sickness.

battle of Sarıkamış is one for the ottoman empire. the lunatic and great idiot called enver paşa sent thousands of soldiers without proper clothing and equipment against the imperial russian army. many of the ottoman soldiers were killed of cold and sickness.

Well, it wasn't humiliating: Ottomans fought well and in harshest and impossible conditions.
It would be like saying that the many defeats suffered by Italian troops in WWI were humiliating, they were not since we fought in the worst front and the Italian soldiers was asked to attack every 3 months, more than any other contender.
Then, Sarikamis was surely an hard defeat but it wasn't humiliating, the fault is of Enver Pasha who was a total idiot.

Not so much humiliating but funny, is the US attack on Guam in the Spanish American War.
The USS Charleston steamed into the harbour at Piti on 10 June 1898 and opened fire on a disused and unmanned old fort, firing thirteen rounds. A crowd gathered at the jetty and notables of the port collected together to welcome the rare and exciting visit of a foreign ship. The local commander of Marines, Captain Pedro Duarte, send a boat out to the Charleston with a message apologising for not being able to return the Naval salute as they had no guns at Piri. However there were some old guns at Agana and if the Americans could kindly lend them some gunpowder, they would be glad to return the honour. Duarte explained that they had no gunpowder or munitions on the island at all and invited Captain Glass and his officers to lunch.
He was really annoyed when the Americans arrived on shore and explained that war had been declared and all of the Spanish officers were prisoners of war.